Transporting and stacking means with a correlated position sensing and load sensing means

ABSTRACT

Transporting and stacking means adapted to pick up unit loads such as palletized or crated goods and automatically stack or store them at predetermined positions comprises position sensing means mounted on the transporting and stacking means and arranged to stop position-seeking movement of the transporting and stacking means at a definite position in relation to a fixed point or series of fixed points and a unit load-sensing means comprising mechanical elements which engage the sides of a unit load being supported by the transporting and stacking means through which position sensing means is automatically moved on its mounting to a position related to the unit being transported so that position-seeking movement of the transporting and stacking means will stop at a position related to that of the unit load irrespective of the relative position of the transporting and stacking means.

United States Patent [72] Inventor Norman George Reading Stockport, England 853,013

B6 MN m 2 Md 0 e win aw hU CB 50 67 99 H 53 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Raymond B. Johnson Attorney-Norris & Bateman ABSTRACT: Transporting and stacking means adapted to pick up unit loads such as palletized or erated goods and automatically stack or store them at predetermined positions comprises position sensing means mounted on the transporting and stacking means and arranged to stop position-seeking movement of the transporting and stacking means at a definite 214/164 position in relation to a fixed point or series of fixed points and B65B1/06 a unit load-sensing means comprising mechanical elements 214/164, which engage the sides of a unit load being supported by the 16-42, 95 transporting and stacking means through which position sensing means is automatically moved on its mounting to a [2 1] Appl. No.

221 Filed Aug. 26, 1969 [45] Patented June 29, 1971 [73] Assignee Simon Handling Engineers Limited [54] TRANSPORTING AND STACKING MEANS WITH A CORRELATED POSITION SENSING AND LOAD SENSING MEANS 4 Claims, 2 Drawing Figs.

51 Int.

[50] Field of [56] References Cited UNITED STATES PATENTS 2,803,356 8/1957 Thomas........................ 3,034,675

position related to the unit being transported so that positionseeking movement of the transporting and stacking means will 214/ l 6.4 stop at a position related to that of the unit load irrespective of the relative position of the transporting and stacking means.

5/1962 Quayle...........v..i.......... 214/730 PATENTFH' JIJN29 m1 INVENTOR NORMAN GEORGE READING ATTORNEYS JYMMQ @[Hlm a TRANSPORTING AND STA'CKING MEANS Wll'llllil A CORRELATEI) POSITION SENSING AND LOAD SENSING MEANS THIS INVENTION relates to transporting and stacking means for handling bulked goods and the like, and is particularly concerned with transporting and stacking means such as stacker cranes, forklift trucks, and similar equipment adapted to pick up unit loads comprising palletized or crated goods and automatically stack or store them at predetermined positions.

It is known to provide much equipment with position detecting means which may comprise a photoelectric cell, proximity switch or other means arranged to arrest position-seeking movement of the said equipment at a definite position in relation to a fixed point or series of fixed points so that a transported unit load can be stacked or stored at the located position, and usually such arrangements provide that the accuracy of position location by the said equipment permits a tolerance of error of the order of 1 inch on either side of a desired point.

It is a disadvantage of such known arrangements that each time a particular unit load is picked up, moved to a desired fixed point, and put down again, the permitted tolerance of error of location of the said equipment may lead to a locational misalignment, between the said unit load and the new desired fixed point, of up to 2 inches, and as such total possible misalignment can increase according to the number of times the particular unit load is so moved, an unacceptable error of unit load positioning can occur.

The object of this invention is to provide means wherein this disadvantage is substantially eliminated.

According to the present invention, transporting and stacking means adapted to pick up unit loads such as palletized or crated goods and automatically stack or store them at predetermined positions, and comprising position sensing means mounted on the transporting and stacking means and arranged to stop position-seeking movement of the said transporting and stacking means at a definite position in relation to a fixed point or series of fixed points, is provided with a unit load sensing means whereby the said position sensing means is automatically moved on its mounting to a position related to the unit load being transported, so that the position-seeking movement of the said transporting and stacking means will stop at a position related to that of the unit load irrespective of the relative position of the transporting and stacking means.

Preferably the unit load-sensing means comprises mechanical elements which engage the sides of a unit load being sup ported by the transporting and stacking means and automatically cause the position sensing means to be moved to a position in line with the vertical centerline of the said unit load.

The load-sensing means may include mechanical elements whereby the position sensing means is automatically moved to and retained in a position related to the transporting and stacking means when no unit load is supported thereby.

The invention will now be described by way of example with reference to the accompanying drawing wherein:

FIGJ l is a pictorial representation of a forklift truck embodying the invention, and

FIG. 2 is a diagrammatic representation of the invention showing the positions taken up by the relatively moveable parts after a load has been picked up.

The position sensing means for stopping position-seeking movement of the transporting and stacking means 111 at a definite position in relation to a fixed point such as the points indicated by markers 12 is so mounted on a structural element 13 of the transporting and stacking means as to be relatively moveable along the path of movement of the transporting and stacking means. Also mounted from the structural element 13 if the transporting and stacking means is a pair of lever arms i each arranged for independent movement in a direction parallel to the path of movement of the transporting and stacking means, and there being, between the position-sensing means and each of the said lever arms, one of a pair of substantially identical resilient elements 15 whereby the positionsensing means is constrained to move in a direction and by an amount determined by the relative positions to which the lever arms are moved. The ends of the lever arms remote from the said resilient elements are shaped as feelers to be engaged and forced apart by vertical side surfaces of a unit load supported by the transporting and stacking means, such parting movement of the feeler ends of the lever arms causing the positionsensing means to be moved automatically by the said resilient elements, from a position related to the centerline 18 of the transporting and stacking means, to a position related to the vertical centerline 19 of the supported unit load.

The position-sensing means is linked to the transporting and stacking means by a dashpot device 16 arranged to damp out undesirable oscillatory movement of the position-sensing means.

Extending from a structural element of the transporting and stacking means so as to project into the paths of convergent movement of the said lever arms are two stop elements 17 which are so spaced apart, equidistantly on each side of the normal centerline of the position-sensing means, that when they are engaged by their respective lever arms the distance between the feeler parts of the lever arms is less than the distance between the engagement side surfaces of the unit loads to be carried.

In operation, the picking up of a unit load causes the feeler ends of the lever arms to be moved apart so that each lever arm is moved by an amount determined by the relative position of the associated side surface of the unit load, and consequently the position-sensing means takes up a position whereat the forces applied to it by the lever-operated resilient elements are in balance, such position being that at which the position-sensing means is at a position related to the vertical centerline of the supported unit load.

When a unit load is put down after being transported, the lever arms move into engagement with their associated stop elements, and the position-sensing means is automatically restored to its normal position where the forces applied by the resilient elements are again in balance and the position of the position-sensing means relates to the position of the transporting and stacking means.

By use of this invention, transported unit loads are always put down at positions located within the permitted tolerance of error, irrespective of the number of times such unit loads have been moved from one position to another.

What we claim is:

I. Transporting and stacking means adapted to pick up unit loads such as palletiaed or crated goods and automatically stack or store them at predetermined positions, and comprising position-sensing means mounted on the transporting and stacking means and arranged to stop position-seeking movement of the said transporting and stacking means at a definite position in relation to a fixed point or series of fixed points, wherein there is provided a unit load-sensing means operatively connected to said position sensing means whereby the said position-sensing means is automatically moved on its mounting to a position related to the unit load being transported in response to the movement of the unit load sensing means engaging said unit load, so that the position-seeking movement of the said transporting and stacking means will stop at a position related to that of the unit load irrespective of the relative position of the transporting and stacking means.

2. Transporting and stacking means as claimed in claim 1 wherein the unit load sensing means comprises mechanical elements which engage the sides of a unit load being supported by the transporting and stacking means and automatically cause the position-sensing means to be moved to a position in line with the vertical centerline of the said unit load.

3. Transporting and stacking means as claimed in claim 1 wherein the load-sensing means includes mechanical elements whereby the position-sensing means is automatically moved to and retained in a position related to the transporting and stacking means when no unit load is supported thereby.

out undesirable oscillatory movement of the position-sensing means. 

1. Transporting and stacking means adapted to pick up unit loads such as palletized or crated goods and automatically stack or store them at predetermined positions, and comprising positionsensing means mounted on the transporting and stacking means and arranged to stop position-seeking movement of the said transporting and stacking means at a definite position in relation to a fixed point or series of fixed points, wherein there is provided a unit load-sensing means operatively connected to said position sensing means whereby the said position-sensing means is automatically moved on its mounting to a position related to the unit load being transported in response to the movement of the unit load sensing means engaging said unit load, so that the position-seeking movement of the said transporting and stacking means will stop at a position related to that of the unit load irrespective of the relative position of the transporting and stacking means.
 2. Transporting and stacking means as claimed in claim 1 wherein the unit load sensing means comprises mechanical elements which engage the sides of a unit load being supported by the transporting and stacking means and automatically cause the position-sensing means to be moved to a position in line with the vertical centerline of the said unit load.
 3. Transporting and stacking means as claimed in claim 1 wherein the load-sensing means includes mechanical elements whereby the position-sensing means is automatically moved to and retained in a position related to the transporting and stacking means when no unit load is supported thereby.
 4. Transporting and stacking means as claimed in claim 1 wherein the position-sensing means is linked to the transporting and stacking means by a dashpot device adapted to damp out undesirable oscillatory movement of the position-sensing means. 